1. Field of the Invention:
This invention relates to pharmacological treatment and prevention of retinal edema and more particularly to treatment and prevention of cystoid macular edema by administration of dopaminergic antagonists.
2. Description of the Prior Art:
Retinal edema is a physiological condition characterized by accumulation of excess fluid in the retina of the eye. A particularly troublesome type of retinal edema is cystoid macular edema (CME), a condition in which small cysts filled with a watery fluid form principally in the inner nuclear layer and outer plexiform layer of the retina, in and around the macula. Since the macular area of the retina is the location of the most acute vision, CME is particularly detrimental to vision. CME is associated with a number of diseases, e.g., hypertensive vascular diseases and diabetes. However, a particularly difficult form of the disease is CME which follows successful cataract extraction. In a relatively high percentage of cases, cystoid macular edema develops some weeks after surgery, resulting in a deterioration of the vision which had been restored by successful cataract extraction. In most patients the condition gradually clears spontaneously, but in some it persists and affects their vision more or less permanently. The cause of CME is unknown, and hitherto there has been no certainly effective treatment for the condition.
A number of treatments have been proposed for alleviating CME after cataract surgery. Since it is believed that retinal trauma produced by tension on retinal attachments of the vitreous may be a cause of CME, cases of chronic CME have been treated with some success by surgical severing of vitreous strands attached to the surgical wound (Fung, W. E., Ophthalmology 89(8), 898-901 (1982)).
Because of the association of CME with inflammatory conditions of the eye, topical and systemic anti-inflammatory drugs have been administered. Corticosteroids and non-steroid anti-inflammatories, e.g. ibuprofen, indomethacin, have been used, and have apparently been of some use in alleviating the condition (Jampol, L. M., Ophthalmology 89(8), 891-897 (1982)). However, no completely reliable treatment for CME has been discovered hitherto.
Therefore a need has continued to exist for a method of treating and preventing retinal edema and particularly cystoid macular edema, which is effective and reliable.